Semaphore in Piccolo F28035PN/CCS ver 5.1

Sabina Greenberg101872

Other Parts Discussed in Thread: SYSBIOS

Dear support,
We work with Piccolo F28035PN card and build application with SYSBIOS(CCS ver 5.1). that use CAN peripherials. I have CAN bus HWI:

void ECAN1Isr_prev (void) //interrupt#101
{
Semaphore_post(SEM_CAN_MSG_RECEIVED);
}

and the task for receive CAN-data:
while (1)
{  // Wait for a message to be recieved
    Semaphore_pend(SEM_CAN_MSG_RECEIVED, BIOS_WAIT_FOREVER);
   m_SemaphoreCounting++;
}

SEM_CAN_MSG_RECEIVED defined is configuration as:

var SEM_CAN_MSG_RECEIVEDParams = new Semaphore.Params();
SEM_CAN_MSG_RECEIVEDParams.instance.name = "SEM_CAN_MSG_RECEIVED";
SEM_CAN_MSG_RECEIVEDParams.mode = Semaphore.Mode_COUNTING;
Program.global.SEM_CAN_MSG_RECEIVED = Semaphore.create(0, SEM_CAN_MSG_RECEIVEDParams);

After 1-st CAN interrupt arrived the program always increment m_SemaphoreCounting without any relation to HWI interrupts.

What could be the reason of this strange behaviors.

Thanks,Sabina

over 13 years ago

0 judahvang over 13 years ago

TI__Mastermind 32475 points

Sabina,

Are you saying the Semaphore_pend() is not actually pending there until the interrupt comes?

Are you incrementing the semaphore count anywhere else?

Judah

0 Sabina Greenberg101872 over 13 years ago in reply to judahvang

Expert 2780 points

I perform POST in interrupt HWI only ( once ).
I print semaphoreCount value in the HWI and in the task;

HWI:
void ECAN1Isr(void)
{
   Semaphore_post(SEM_CAN_MSG_RECEIVED);
    int semaphoreCountVal = Semaphore_getCount(SEM_CAN_MSG_RECEIVED);
    Log_info2("ECAN1INTA_ISR start, miv = %d, semaphoreCountVal = %d", miv, semaphoreCountVal);
  }

TASK:
int loopCounting = 0;
while (1)
{
   bool semaphorePendReturnVal = Semaphore_pend(SEM_CAN_MSG_RECEIVED, BIOS_WAIT_FOREVER);
  loopCounting++;
   int semaphoreCountVal = Semaphore_getCount(SEM_CAN_MSG_RECEIVED);
   Log_info3("loopCounting = %d, semaphorePendReturnVal = %d, semaphoreCountVal = %d", loopCounting, semaphorePendReturnVal, semaphoreCountVal);
}

output on the console after the 1st interrupt arrived (correct):

ECAN1INTA_ISR start, semaphoreCountVal = 0
loopCounting = 1, semaphorePendReturnVal = 1, semaphoreCountVal = 0"

and output on the console after progtam running without additional HWI interrupts (problematic !!!!):
loopCounting = 38761, semaphorePendReturnVal = 1, semaphoreCountVal = 0
loopCounting = 38762, semaphorePendReturnVal = 1, semaphoreCountVal = 0

It is not clear why Semaphore_pend(SEM_CAN_MSG_RECEIVED, BIOS_WAIT_FOREVER); return true always.

And why semaphoreCountVal = 0 in the HWI?

Thanks, Sabina

0 judahvang over 13 years ago in reply to Sabina Greenberg101872

TI__Mastermind 32475 points

Sabina,

When you create the Semaphore initially, does it have a value of 0?

There's no logical explanation for your problem. If Semaphore_pend() is not functioning properly, it needs to be determined why? It could be the Semaphore count is getting corrupted by something else. Yes a value of 0 for the semaphore count in Hwi definitely points to some problem already because a post should have incremented the value.

Judah

0 Sabina Greenberg101872 over 13 years ago in reply to judahvang

Expert 2780 points

Hi Judah,

Thanks for the reply. I found the source of the problem. I had two different interrupts with the same function that perform Semaphore_post().

Thanks a lot, Sabina

Processors

Processors forum

Semaphore in Piccolo F28035PN/CCS ver 5.1